C-19 Chat Post – February 17 2021

DAYS 1-5 (FEBRUARY 16-20)

Low pressure cuts across the South Coast region this morning before exiting and taking its rainfall with it. After some icing conditions from freezing drizzle & freezing rain in a good portion of the region we thankfully saw the temperature climb to above freezing from southeast to northwest during the overnight, avoiding what could have been a more serious icing situation, but as drier and colder air moves in tonight behind this system, we will indeed have to watch for the formation of black ice on any untreated surfaces that are still wet – and there will likely be quite a few. High pressure brings bright and cold weather to our region Wednesday before the next in a series of low pressure areas makes a run at us later Thursday, passing just south of the region early Friday. This system will have colder air to work with and start as snow, with a few to several inches likely before a flip to sleet / freezing rain / rain, the details of which will be worked out for the next two blog updates. This storm system exits later Friday and sets us up for a cold and dry start to the weekend.

TODAY: Overcast with areas of rain (a few pockets of icing still possible interior valleys of north central MA and southwestern NH) this morning. Mainly cloudy with areas of fog this afternoon. Highs 33-40 except 40-47 far southeastern MA. Wind E to N 5-15 MPH except may be briefly SE to SW 10-20 MPH and gusty Nantucket area.

TOIGHT: Clearing. Lows 16-23. Wind N to NW 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 25-32. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Increasing high clouds. Lows 13-20. Wind N up to 10 MPH.

THURSDAY: Thickening overcast. Snow arriving southwest to northeast late day. Highs 25-32. Wind NE 5-15 MPH.

THURSDAY NIGHT: Overcast. Snow/sleet/freezing rain/rain likely, with greatest chance for frozen precipitation interior and north, greatest chance for freezing and/or liquid precipitation coast and south. Temperatures rise to 28-35. Wind NE to E 5-15 MPH.

FRIDAY: Overcast with snow/sleet/ice/rain morning. Breaking clouds afternoon. Highs 33-40. Wind E to N 5-15 MPH morning, NW 10-20 MPH afternoon.

FRIDAY NIGHT: Clearing. Lows 18-25. Wind NW 10-20 MPH.

SATURDAY: Partly cloudy. Highs 27-34. Wind NW 10-20 MPH.

DAYS 6-10 (FEBRUARY 21-25)

High pressure from Canada delivers dry but cold weather for the February 21. Disturbance from the west brings precipitation threat February 22-23 followed by fair and seasonably cold weather to end the period.

DAYS 11-15 (FEBRUARY 26 – MARCH 2)

We may see a transition out of blocking into more of a west zonal pattern with a storm track bringing weaker systems over or north of the region with a couple precipitation chances and some temperatures swings.

C-19 Chat Post – February 16 2021

DAYS 1-5 (FEBRUARY 15-19)

One wave of low pressure is passing south of us today, but a more important low pressure area will come at the region tonight into Tuesday. While the track of this low will be across the South Coast region or even just south of the region, with the strength of a ridge of high pressure over the southeastern US and a slight retreat of the arctic air that had leaked into the Northeast we now see the ability for it to warm up a little more above us as this system passes by. But, as we know, cold air is still in place here at the surface and is very often tough to dislodge, especially with a storm tracking as it is, instead of west of the area. So while it is cold enough for spotty and fairly insignificant mostly frozen precipitation today, once the main shield of moisture arrives tonight into Tuesday and it warms aloft for rain to be falling across the area, that rain will be freezing upon contact with the surface in a fair amount of the region due to below-freezing temperatures at ground level. The precise location of that freezing line during the event will determine who ends up with icing conditions and who escapes them. It’s a fairly safe bet that most if not all areas outside the I-95 belt will experience at least some icing, and areas that stay freezing rain for the duration will experience the most significant icing, with between 1/4 and 1/2 inch of ice accretion likely. The I-95 belt including Metro Boston and even Metro Providence initially will be more “on the line” and more vulnerable to areas that are icy and areas that are not because of marginal temperatures, while the coastal plain and especially the South Shore of MA and South Coast region will be least likely to experience any icing conditions. Please use utmost caution if you have to travel during this event. After this first messy bout of precipitation tapers off as the low pulls away later Tuesday, a clearing sky and quick temperature drop that night will lead to black ice formation on any untreated wet surfaces, including areas that had been above freezing and ice-free during the precipitation, so continued extreme caution walking or driving is a must from Tuesday night right into Wednesday, which will be a dry but cold day between storm systems. Yup, systems, because another one is heading in for Thursday into Friday, and this one, having more cold to work with at least initially, is bound to bring a little more snow with it to start out, arriving during Thursday afternoon and evening from southwest to northeast. But while the primary low pressure area responsible for this bout of unsettled weather has its eyes on a path northwest of here, high pressure in Canada will hold up a stop sign and the low will kind of “Jello” its way just south of New England, basically transferring its energy along a trough line where the border of the cold and warm air is, and re-emerge as a new low offshore which will then move away during Friday and Friday night. During this process once again we should see some warming aloft so that at least a portion of the region will experience sleet and freezing rain and/or rain (depending on temperature profile). For this system I’ll keep the forecast more generalized and then try to detail the precipitation set-up during the next couple of blog posts leading up to the event.

TODAY (PRESIDENTS DAY): Cloudy. Occasional light snow/sleet likely, with freezing rain/rain possible. Minor snow/sleet accumulation possible. Light glazing of ice possible. Highs 27-34. Wind N up to 10 MPH.

TONIGHT: Cloudy. Increasing coverage of snow/sleet/freezing rain/rain evening, with additional minor snow/sleet accumulation mostly northwest of Boston, changing to freezing rain & rain overnight with significant glazing likely where temperatures are below freezing. Temperatures steady 27-34 evening, rising slightly overnight. Wind N to NE 5-15 MPH.

TUESDAY: Overcast. Rain coastal areas and freezing rain interior especially west and north of Boston morning, tapering off afternoon. Additional icing likely over interior locations. Highs 30-37 interior locations, coldest in valleys of north central MA and southern NH, 38-45 in coastal locations, mildest over Cape Cod, except briefly near 50 possible Nantucket. Wind E to N 5-15 MPH except may be briefly SE to SW 10-20 MPH and gusty Nantucket area.

TUESDAY NIGHT: Clearing. Lows 18-25. Wind N to NW 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 25-32. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Increasing high clouds. Lows 13-20. Wind N up to 10 MPH.

THURSDAY: Thickening overcast. Snow arriving southwest to northeast late day. Highs 25-32. Wind NE 5-15 MPH.

THURSDAY NIGHT: Overcast. Snow/sleet/freezing rain/rain likely, with greatest chance for frozen precipitation interior and north, greatest chance for freezing and/or liquid precipitation coast and south. Temperatures rise to 28-35. Wind NE to E 5-15 MPH.

FRIDAY: Overcast with snow/sleet/ice/rain morning. Breaking clouds afternoon. Highs 33-40. Wind E to N 5-15 MPH morning, NW 10-20 MPH afternoon.

DAYS 6-10 (FEBRUARY 20-24)

High pressure from Canada delivers dry but cold weather for the February 20-21 weekend. Disturbance from the west brings precipitation threat February 22-23 followed by fair and seasonably cold weather to end the period.

DAYS 11-15 (FEBRUARY 25 – MARCH 1)

We may see a transition out of blocking into more of a west zonal pattern with a storm track bringing weaker systems over or north of the region. This would produce a couple risk of precipitation and some swings in temperature. This is a fairly low confidence forecast at this time.

C-19 Chat Post – February 15 2021

DAYS 1-5 (FEBRUARY 14-18)

The pattern is the same – we remain in the moisture conveyor belt between cold air to the north and west and warm air over the southeastern US. Adjustments to the outlook have been made to indicate more warming aloft due to a stronger ridge of high pressure – yes the ridge we’ve waited for to appear, nearly declared a total failure, then decides to show up in this La Nina pattern. Anyway here we go with a continued series of low pressure areas moving along. We’ve had one go by last night and early today, causing some slippery roads from freezing rain/drizzle near the South Coast, and the next one Monday will really just contain a spotty light precipitation variety. There are two more coming along that have more moisture to work with, Tuesday, and Thursday night into Friday, with a dry/cold interlude Wednesday. Each of these final two systems can produce a complex precipitation pattern with snow, sleet, freezing rain, and rain, depending on the temperature profile of the atmosphere and temperatures at the surface. That’ll be fun to figure out over the coming days…

TODAY: Cloudy. Highs 27-34. Wind N up to 10 MPH.

TONIGHT: Cloudy. Lows 22-29. Wind N up to 10 MPH.

MONDAY (PRESIDENTS DAY): Cloudy. Occasional light snow/sleet likely, with freezing rain/drizzle possible. Highs 27-34. Wind N 5-15 MPH.

MONDAY NIGHT: Cloudy. Spotty light snow or snow/sleet mix evening. Steady snow/sleet/freezing rain/rain arriving overnight. Temperatures steady 27-34. Wind N to NE 5-15 MPH.

TUESDAY: Overcast. Snow/sleet/freezing rain/rain likely, tapering off from west to east later in the day. Highs 29-36. Wind NE to N 5-15 MPH.

TUESDAY NIGHT: Clearing. Lows 18-25. Wind N to NW 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 25-32. Wind NW 5-15 MPH.

WEDNESDAY NIGHT: Increasing high clouds. Lows 13-20. Wind N up to 10 MPH.

THURSDAY: Thickening overcast. Snow arriving by late-day, may turn to sleet/freezing rain/rain at night. Highs 25-32, but temperatures may rise at night. Wind NE 5-15 MPH.

DAYS 6-10 (FEBRUARY 19-23)

Mix/rain most likely February 19 as low pressure passes by the region probably just to the south. Dry, seasonably cold February 20-21 weekend. Another disturbance may bring some snow/mix to the region in the February 22-23 window.

DAYS 11-15 (FEBRUARY 24-28)

We may see a transition out of blocking into more of a west zonal pattern with a storm track bringing weaker systems over or north of the region. This would produce a couple risk of precipitation and some swings in temperature.

C-19 Chat Post – February 14 2021

DAYS 1-5 (FEBRUARY 13-17)

We’ll continue to be in the battle zone between entrenched arctic air over a good portion of the country and a warmer southeastern US due to the appearance of a high pressure ridge, finally, long after it was initially expected. While none of the low pressure areas moving along this boundary will be particularly strong, we do have 3 to contend with during this 5-day period, the first of which comes by tonight and early Sunday with light precipitation, the second during Monday again with fairly light precipitation, and the third and most moisture-laden system to follow later Monday night through Tuesday. The biggest question to answer with these is how much warm air will come in aloft to result in a variety of precipitation rather than mostly snow. At the surface, we will be on the cold side of the boundary for the duration, but that means that if we warm up aloft we’ll deal with at least sleet becoming part of the deal, and if we warm up enough we’ll end up with a freezing rain issue where surface temperatures remain below freezing. So this will be the puzzle to solve… Meanwhile, this unsettled stretch will be book-ended by dry weather during the day today and Wednesday, following the departure of the third system.

TODAY: Partly sunny. Highs 24-31. Wind N 5-15 MPH.

TONIGHT: Mostly cloudy. Snow arriving overnight from west to east. Lows 17-24. Wind NE 5-15 MPH.

SUNDAY: Mostly cloudy. Spotty snow & possible freezing drizzle into midday. Any snow accumulation mostly coatings. Chance of minor icing. Highs 25-32. Wind NE to N up to 10 MPH.

SUNDAY NIGHT: Mostly cloudy. Spotty light snow and sleet possible. Lows 15-22. Wind N up to 10 MPH.

MONDAY (PRESIDENTS DAY): Cloudy. Occasional light snow/sleet likely, with freezing rain/drizzle possible. Highs 25-32. Wind N 5-15 MPH.

MONDAY NIGHT: Cloudy. Spotty light snow or snow/sleet mix evening. Steady snow arriving overnight. Lows 18-25. Wind N to NE 5-15 MPH.

TUESDAY: Overcast. Snow/sleet/freezing rain/rain likely, trending toward mostly snow. Highs 26-33. Wind NE 10-20 MPH.

TUESDAY NIGHT: Clearing. Lows 18-25. Wind NW 5-15 MPH.

WEDNESDAY: Mostly sunny. Highs 25-32. Wind NW 5-15 MPH.

DAYS 6-10 (FEBRUARY 18-22)

Another low pressure area likely brings unsettled weather with a variety of precipitation possible in the February 18-19 window, favoring cold solution. Fair, cold weather to follow for the February 20-21 weekend before next system has to be watched for the end of the period.

DAYS 11-15 (FEBRUARY 23-27)

One or two more possible precipitation threats during this period. Temperatures near to below normal.

C-19 Chat Post – February 13 2021

DAYS 1-5 (FEBRUARY 12-16)

The pattern is locked in. Very cold air centered on the west central and central US while we are cold here, but more as the air “leaks” into our area. This is how this was expected to evolve, and it has. Also, in this pattern, while you can get significant storm systems that dump a decent amount of precipitation, you don’t tend to get anything resembling “blockbusters”. This will continue to to be the case, with a series of disturbances along the boundary of cold and warmer air associated with the late-arriving and less expansive Southeast ridge will being the watchers for our “weather events”. Recent events have ended up less than their potential (the Tuesday event which produced less than expected, the Thursday event which grazed the South Coast, and today’s non-event, a.k.a. miss to the south. The upcoming system for early Sunday also looks anemic, a minor snow producer at best. But a little shift for today’s update, and something I must note (for model watchers) was picked up first by the Canadian guidance) is that there will be a string-out of energy enough that we’ll probably stay in a fair amount of cloudiness and even have a bit of a precipitation (snow/mix) threat Monday in between the Sunday system and the one with the greatest potential, slated for Tuesday. That final one, keeping in mind it’s forecast day 5, holds the best potential to produce a more significant amount of precipitation. I’ll keep it vague at day 5, as trying to detail anything beyond day 3 is a waste of time.

TODAY: Sunny morning. Partly sunny afternoon. Highs 23-30. Wind NW 5-15 MPH.

FRIDAY NIGHT: Partly cloudy. Lows 11-18. Wind N 5-15 MPH.

SATURDAY: Partly sunny. Highs 24-31. Wind N 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Snow arriving overnight from west to east. Lows 17-24. Wind NE 5-15 MPH.

SUNDAY: Mostly cloudy through early afternoon with occasional snow, except possible mix South Coast. Snow accumulation spotty and under 2 inches. Breaking clouds later. Highs 27-34. Wind NE to N 5-15 MPH.

SUNDAY NIGHT: Variably cloudy. Lows 10-17. Wind N 10-20 MPH.

MONDAY (PRESIDENTS DAY): Mostly cloudy. Spotty light snow or snow/sleet mix possible. Highs 22-29. Wind N 10-20 MPH.

MONDAY NIGHT: Cloudy. Spotty light snow or snow/sleet mix evening. Steady snow arriving overnight. Lows 18-25. Wind N to NE 5-15 MPH.

TUESDAY: Overcast. Snow/mix/rain likely (early idea favors frozen most of region, greatest rain risk South Coast). Highs 26-33. Wind NE 10-20 MPH.

DAYS 6-10 (FEBRUARY 17-21)

Dry interlude February 17. Next window of opportunity for unsettled weather later February 18 into February 19, followed by fair weather later in the period. Temperatures below normal.

DAYS 11-15 (FEBRUARY 22-26)

One or two more possible precipitation threats during this period. Temperatures near to below normal.

C-19 Chat Post – February 12 2021

DAYS 1-5 (FEBRUARY 11-15)

This 5-day segment takes us through the Presidents Day Weekend, and during this period we will have 3 low pressure systems pass our longitude in the continued cold and active weather pattern. No, this is no 2015, when we were in a much higher amplitude pattern with cold so locked in that our storms were all big powder fluff snowstorms – this one has a different set-up. It’s cold, yes, but we set at the eastern edge of a large cold air mass which dominates a good portion of the US, while far southeastern portions of the US, especially Florida, has been sitting in very warm air. The boundary zone between that cold & warm is always the most vulnerable area for storms to be, and a quick jet stream moves a steady series of them along the boundary. The first of the three aforementioned low pressure areas passes to the south of New England today, close enough only to bring brief snow around the South Coast for a brief time, while the remainder of the area just starts to the day under a canopy of clouds, which will then clear out. The second low pressure area passes even further south of the region on Friday, leaving us with a partly sunny and dry day. The next low makes a run at the region on Sunday, Valentine’s Day, but will be losing punch as it does so. At this point, my expectation from this one is that we can squeeze out a generally light snowfall from late Saturday night as moisture streams in ahead of the system, through Sunday midday before drier air has sufficiently eaten away at the system that we probably end the day with at least some sun. Presidents Day Monday is expected to be dry but breezy and cold between that departing low to the east and approaching high pressure from the west.

TODAY: Mostly cloudy early morning with brief light snow South Coast. Increasing sun thereafter. Highs 24-31. Wind N up to 10 MPH.

TONIGHT: Parttly cloudy. Lows 13-20. Wind N up to 10 MPH.

FRIDAY: Partly sunny. Highs 23-30. Wind NW 5-15 MPH.

FRIDAY NIGHT: Partly cloudy. Lows 11-18. Wind N 5-15 MPH.

SATURDAY: Mostly sunny. Highs 24-31. Wind N 5-15 MPH.

SATURDAY NIGHT: Mostly cloudy. Snow arriving overnight from west to east. Lows 17-24. Wind NE 5-15 MPH.

SUNDAY: Cloudy through early afternoon with probable snow, except possible mix South /Coast. Breaking clouds later. Highs 27-34. Wind NE to N 5-15 MPH.

SUNDAY NIGHT: Partly cloudy. Lows 10-17. Wind N 10-20 MPH.

MONDAY (PRESIDENTS DAY): Partly sunny,. Highs 22-29. Wind N 10-20 MPH.

DAYS 6-10 (FEBRUARY 16-20)

Current timing brings our next storm threat in for February 16, likely a more significant snow to mix event, details to be determined. Dry weather follows for February 17. Quick-moving systems in the jet stream mean that the next threat will be sooner, sometime in the February 18-19 time window with dry weather returning to end the period.

DAYS 11-15 (FEBRUARY 21-25)

One or two more possible precipitation threats during this period. Temperatures near to below normal.

C-19 Chat Post – February 11 2021

DAYS 1-5 (FEBRUARY 10-14)

High pressure brings fair and cold winter weather today. One low pressure area will pass south of the region Thursday, but may be close enough to bring a touch of light snow into the South Coast region before moving on. A follow-up low will pass even further south of the area on Friday with no snow threat. High pressure slides back in for fair but cold weather Saturday. Sunday, we’ll have to watch for a storm system coming at us from the southwest, but it’s uncertain at this point how significant this one will be for us. It does have some potential as it should have more connection with southern moisture – something to watch and fine-tune the next few days.

TODAY: Early clouds eastern areas, otherwise mostly sunny. Highs 26-33. Wind W 5-15 MPH.

TONIGHT: Clouds return. Lows 12-19. Wind NW under 10 MPH.

THURSDAY: Mostly cloudy. A bit of very light snow possible South Coast. Highs 24-31. Wind N up to 10 MPH.

THURSDAY NIGHT: Mostly cloudy. Lows 13-20. Wind N up to 10 MPH.

FRIDAY: Partly sunny. Highs 23-30. Wind NW 5-15 MPH.

FRIDAY NIGHT: Partly cloudy. Lows 11-18. Wind N 5-15 MPH.

SATURDAY: Mostly sunny. Highs 24-31. Wind N 5-15 MPH.

SATURDAY NIGHT: Increasing clouds. Lows 17-24. Wind NE 5-15 MPH.

SUNDAY: Cloudy. Snow/mix/rain possible. Highs 25-30 north, 30-35 south. Wind NE 10-20 MPH.

DAYS 6-10 (FEBRUARY 15-19)

Windy/cold/dry February 15 behind the late weekend storm threat. February 16-17 is the next storm threat – more detail to come in days ahead. Dry/cold February 18-19.

DAYS 11-15 (FEBRUARY 20-24)

One or two more possible precipitation threats during this period. Temperatures near to below normal.

C-19 Chat Post – February 10 2021